1. Field of the Invention
The present invention relates to a power supply device for an electric vehicle. More particularly, the invention relates to a power supply device for an electric vehicle that is suitable for providing a simple structure for detachably supporting a battery pack, with battery cells accommodated therein, to a vehicle body.
2. Description of Background Art
Conventionally, in an electric vehicle, a battery pack having a plurality of battery cells assembled in a battery case has commonly been mounted as a power supply device at a center portion of a frame of the electric vehicle. For instance, in a battery lock structure for the electric bicycle described in Japanese Patent Laid-open No. 2000-142551, a support shaft and an engagement projection are provided on the battery side. On the other hand, a tentative positioning part and a locking surface part are provided for engaging the support shaft and the engagement projection on the battery side. Brackets, each formed with a guide surface part for guiding the support shaft and a relief part, are provided on the electric bicycle side. At the time of mounting the battery to the vehicle body from a lateral side of the vehicle body, the battery is moved to the tentatively positioning part, while setting the support shaft along the guide surface parts of the brackets. Furthermore, the battery is turned toward the vehicle-width-directionally inner side, with the support shaft supported on the tentative positioning part as a center of turning. The engagement projection is locked to the locking surface part as a wedge. According to this electric bicycle, the tentative positioning and the locking of the battery are carried out using different component parts, namely, the support shaft and the engagement projection. Consequently, the battery after mounted can be prevented from chattering.
In the electric bicycle, electrical connection parts are necessary for supply of electric power from the battery mounted onto the vehicle body to a motor, etc. provided as electrical equipments on the vehicle body side (the electrical connection parts are not clearly shown in Japanese Patent Laid-open No. 2000-142551). On the vehicle body side, therefore, the above-mentioned brackets are provided as additional members for holding the electrical connection parts onto the vehicle body. Thus, the number of component parts is increased. In addition, the support shaft and the engagement projection, etc. are provided at an outer circumferential surface of the battery. This results in that at the time of carrying or storing the battery, extra care should be taken in handling the battery so as not to damage the support shaft or the engagement projection or the like by mistake.